Question

What is the derivative of this function y= 2x sinx + x^2 cosx ?

Answer 1

you have to use the power rule on each part of the equation, so for 2xsinx it would be
2sinx+2xcosx.... so on

Answer 2

But do I have to change sinx to cos x and cos x to - sinx ?

Answer 3

2sinx+2xcosx+2xcosx-x^2sinx

Answer 4

use the product rule then once it is expanded use the fact that the derivative of sinx=cosx and cosx=-sinx

Answer 5

After i expand it i get (2)(x)(sin x) + (x^2) (cos x)
then i get y prime = 2 cos x + 2x - sin x
is that right or am I doing something wrong ?